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Do short sleepers drink more?

Today’s post comes courtesy of my uOttawa colleague Jessica McNeil, who recently co-authored a paper that has generated a lot of interest on the relationship between sleep and alcohol. You can find out more about Jess at the bottom of this post.

Sleep duration is associated with alcohol consumption in adults

Background

The increases in shift work and overtime hours, family and social demands, as well as time spent watching television and browsing the Internet (Alvarez & Ayas, 2004) have shaped a society which is operational 24 hours a day, 7 days a week. However, in order to accomplish these many demands, many choose to voluntarily decrease their sleep time, which may in turn lead to metabolic and health problems over time (Cappuccio et al., 2008). Chaput et al. (2008) have previously noted that adult chronic short sleepers (< 6 hours of sleep/night) tend to have greater body weight, body mass index (BMI), body fat percentage and abdominal circumference when compared to average sleepers (7-8 hours of sleep/night). Short sleep duration was further associated with an increase risk of weight and fat mass gains over time in adults (Chaput et al., 2008), making it an important risk factor for the development of obesity with odds ratio exceeding other well-known contributors (e.g. high dietary lipid intake and the nonparticipation in high-intensity physical activity, with odds ratios of 1.64 and 2.03 respectively vs. 3.81 for short sleep duration) (Chaput et al., 2009).

In addition to the increase in the prevalence of short-duration sleepers (7.6% in 1975 to 9.3% in 2006; (Knutson et al., 2010), in Canada, both the annual volume of alcohol consumption and the prevalence of high-risk drinking have increased over the last decade (Health Canada, 2008; Statistics Canada, 2008). And so, an observational, cross-sectional analysis (Chaput et al., 2012) was done in order to investigate the relationship between sleep duration and alcohol intake in adults from the greater Quebec city area. In the following paragraphs, I will be addressing the major findings of this study, as well as mentioning an upcoming study that will help us further understand the potential underlying causes of alcohol intake, sleep duration and sleep quality on next day food intake.

What we did

Adults who were between the ages of 18 and 64 years and who were tested during phases 2 and 3 of the Quebec Family Study were selected for cross-sectional analyses (703 individuals; 301 men and 402 women). Sleep duration was assessed with a question in a self-administered questionnaire on physical activity participation. The question read: “On average, how many hours do you sleep a day?”. We classified the participants into 3 sleep-duration groups: short-durations sleepers (< 6 hours of sleep/night), average-duration sleepers (7-8 hours of sleep/night) and long-duration sleepers (> 9 hours of sleep/night).

Participants’ diet, which included alcohol intake, was evaluated with a 3-day food record. This food record provided us with information on food and beverage intake measured over 2 week days and 1 weekend day. Participants were also asked, as part of a self-administered questionnaire, about the number of alcoholic beverages that they generally consume during 1 occasion. A drink was defined as 341 mL (12 oz) glass of beer (5% alcohol by volume),142 mL (5 oz) glass of wine (12% alcohol) or 43 mL (1.5 oz) glass of spirits (40% alcohol), which is based on standard alcohol servings in Canada. Lastly, participants completed the Three-Factor Eating Questionnaire, which was used to assess disinhibition eating behavior (i.e. overconsumption of food in response to cognitive, emotional and/or social cues) in this study.

What we found

Overall, short-duration sleepers consumed significantly more alcohol when compared to average- and long-duration sleepers. More specifically, short-duration sleepers consumed more beer in 1 occasion when compared to average-duration sleepers, while overall liquor consumption was also greater in short-duration sleepers when compared to both average- and long-duration sleepers.

Short sleep duration was also associated with increased odds (i.e. odds ratio of 1.87 for both sexes combined) of exceeding the guidelines for sensible weekly alcohol consumption (i.e. 14 drinks/week for men and 7 drinks/week for women) when compared to average-duration sleepers, even after adjusting for age, family income, coffee intake, energy intake, and moderate-to-vigorous physical activity participation. Lastly, daily alcohol intake was significantly higher in short-duration sleepers with a high disinhibition eating behavior trait, while the prevalence of binge drinking (i.e. ≥ 5 drinks on 1 occasion) was more common in men than women. And so, men who slept less than 6 hours per night and reported having disinhibited eating behavior were more likely to report binge drinking (41% of reported binge drinking occasions) for either beer, wine or spirits.

Take home message

This study demonstrates that a combination of short sleep duration with a disinhibited eating behavior trait is associated with greater alcohol intake in adults. Sleeping less than 6 hours per night was also associated with an increased risk of exceeding the guidelines for sensible weekly alcohol intake. The finding of greater alcohol intake combined with disinhibited eating behavior may in part explain why adult short sleepers are at a greater risk of gaining more weight and fat mass over time, when compared to average-duration sleepers (Chaput et al., 2008). It may thus be concluded that the phenotype of “disinhibited short sleeper” is more likely to consume larger quantities of alcohol (in both sexes) and to binge drink (in men).

Future directions

It has been previously suggested that 2-3 standard drinks before bedtime initially promotes sleep (Stein & Friedmann, 2005). However, when individuals binge drink (i.e. ≥ 5 drinks in 1 occasion), it has been previously observed that an increase in sympathetic nervous system activity usually occurs when blood alcohol levels falls to 0% (i.e. ≈ half way through the night), which usually leads to a REM rebound and the occurrence of sleep fragmentation (Stein & Friedmann, 2005). Additionally, it has been previously shown that reductions in medial pre-frontal cortex activity, which plays a key role in the reward-seeking process, is associated with greater typical alcohol intake and greater trait disinhibition, during a reward seeking process. Conversely, greater alcohol intake and trait disinhibition were associated with greater increases in medial pre-frontal activity during a reward seeking outcome (Bogg et al., 2012). Lastly, St-Onge et al. (2012) noted greater neuronal activation in the orbitofrontal cortex, an area of the brain related to motivation, in response to food cues when compared to non-food cues following 6 nights of sleep restriction (4 hours of sleep/night).

Taken together, these results suggest that individuals who consume a larger quantity of alcohol and/or have higher disinhibited eating behavior may have an enhanced susceptibility to food cues and their rewarding properties, which may then lead to an increased motivation (or wanting) to consume these items. This effect may also be amplified if individuals are subjected to sleep fragmentation which may be attributed to binge drinking.

My PhD thesis work will include looking at whether the quantity of alcohol intake (i.e. blood alcohol levels of 0.02% and 0.1%) will affect sleep quality, sleep duration, as well as next day food intake and food reward. We hypothesize that heavy alcohol consumption (i.e. blood alcohol level of 0.1%) will remove the cognitive control over feeding and may in part explain why individuals are more prone to consuming a greater quantity of energy-dense foods following alcohol intake (Yeomans, 2010). Furthermore, it is hypothesized that individuals who have greater disinhibition eating behavior and/or who will experience more frequent episodes of sleep fragmentation due to heavy drinking will most likely succomb to food cues and consume a greater amount of kilocalories following a heavy drinking episode.

This study will follow a randomized crossover design, where participants will take part in 3 experimental sessions (i.e. 1 control at 0% blood alcohol level, 1 “light drinking” at 0.02% blood alcohol level and 1 “heavy drinking” at 0.1% blood alcohol level). Sleep duration and sleep quality will be objectively measured through the use of polysomnography (monitors brain and muscle activity, eye movement and heart rhythm during sleep). Next day ad libitum energy intake will be measured with a validated food menu. Lastly, certain behavioral determinants (e.g. dietary restraint, disinhibition eating behavior trait) and food reward (e.g. food “wanting and liking” measured with a forced choice computer task) will also be measured. [Travis’ note: I really want to participate in this study!].

The results of this study will permit us to determine and better understand why certain individuals who drink heavily on 1 occasion may be at a greater risk of energy-dense food intake, which may lead to a surplus of total kilocalorie intake.

Jessica McNeil

About the author: Jessica McNeil is a certified exercise physiologist and a PhD student in the School of Human Kinetics at the University of Ottawa. She is currently working under the supervision of Drs. Éric Doucet and Jean-Philippe Chaput. Her research will focus on the effects of sleep deprivation and alcohol intake on sleep quality, and next day energy intake and food reward.

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Travis Saunders has a PhD in Human Kinetics, and is currently an Assistant Professor in Applied Human Science. His research focuses on the relationship between sedentary time (e.g. sitting) and chronic disease risk in both children and adults. He is also a Certified Exercise Physiologist and (former) competitive distance runner. You can connect with him on Twitter @TravisSaunders.

2 comments

Very interesting post, thanks. Just want to point out a recent meta-analysis with very similar conclusions. There is an informative discussion section in this meta-analysis too. Alcohol indeed seems to reinforce food reward value.